Try closing down all programs running in the background.
Quickest way to do this:
1. Unplug your internet connection (trust me, you want to do this)
2. Go to start > run and type MSCONFIG. Hit enter
3. On the window that appears, click on the tab in the upper right labelled startup
4. Click 'disable all' at the lower right of the window. Click ok
5. Restart when prompted and try the game
If this works then something is running in the background which is preventing the game from starting. Try running through the list of apps on the startup tab and check them one at a time to identify it.
It would also help if you could give us the name of your graphics card